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[UPDATE 2] [Teaser] Is S4GRU 5X certain that this is the new Nexus 5X?




by Tim Yu

Sprint 4G Rollout Updates

Friday, September 25, 2015 - 5:44 PM MDT


Update 2: S4GRU's technical editor here again. It is Monday, October 19, and today is the day. Many of the Nexus 5X first preorders started shipping this morning for delivery later this week. You also may have caught the Nexus 5X television commercial that Google ran multiple times during the NFL broadcasts yesterday.


In light of the first handsets shipping today, S4GRU wants to publish a second update to this article, confirming the correct Sprint SIM card and covering fully the tested FCC OET (Office of Engineering and Technology) ERP/EIRP RF figures, which recently received a Class II Permissive Change filing.


As we speculated a few weeks ago, the correct Sprint SIM for the Nexus 5X is the same 4FF nano SIM as for the 2015 Moto X aka Style aka Pure Edition. It is the latest version Sprint CSIM, so network activation for both LTE and CDMA2000 will be via the SIM. The SIM can acquired for free at a Sprint corporate store with repair center or from Sprint International support online chat. As unlocked, third party handsets are still somewhat rarities on Sprint, some S4GRU users have reported difficulties in obtaining the correct SIM from those official Sprint channels. Your mileage may vary. If you prefer to purchase the correct SIM yourself, you typically can do so at Best Buy Mobile. More detailed info about SIM procurement is available in our newly opened Nexus 5X user thread.


In our original publication of this article almost a month ago, I included a sidebar with some brief discussion of RF power output. It hit just the highlights. As the Nexus 5 still to this day has been known for its solid RF performance on the Sprint network, S4GRU wanted to do a full LTE ERP/EIRP rundown of its Nexus 5X younger sibling in this update. This is especially true in light of the aforementioned Class II filing -- disclosing some "Antenna/PCB adjustments" to the Nexus 5X -- subsequent to the original filing and our original publication. Interestingly, none of the peak antenna gain figures have changed, but perhaps small tweaks below the peak gain or in the body of the handset appear to have affected ERP/EIRP slightly.


For easy readability, I have put together a table to compare ERP/EIRP and antenna gain across the original filing and the Class II filing. See below:




All of the usual disclaimers about lab testing versus real world performance and uplink versus downlink apply. The figures represent my best averaged and rounded estimates of maximum uplink ERP/EIRP test results provided to the FCC OET in the authorization filings for the device.


My previous RF analysis in the originally published article below stands. The Nexus 5X is relatively powerful in low and mid band spectrum, in which we like to see at least 17-18 dBm and 22-23 dBm, respectively. But it is not quite as powerful as we would hope in high band spectrum, which ideally should be 23 dBm or greater. However, the physical changes that warranted the Class II filing do appear to have reduced low and mid band output by a subtle degree -- possibly in exchange for higher and more consistent output in band 41. The RF figures seem to suggest that.


To conclude, if you have ordered the Nexus 5X, watch your mailboxes and doorsteps this week. In the meantime, you can watch the Nexus 5X television commercial on YouTube.



Update: S4GRU's technical editor here. We now have the full Nexus 5X tech specs released from Google, thus can comment on a few issues not disclosed in the FCC OET authorization filings last week. Namely, international band support and SIM card form factor. In addition to the tested domestic bands listed below, the Nexus 5X also supports the following international bands:

  • GSM 900/1800
  • W-CDMA band 1/8
  • LTE band 1/3/20

For those unfamiliar, band 1 is IMT 1900+2100 MHz, band 3 is DCS 1800 MHz, band 8 is GSM 900 MHz (or what SoftBank calls the "Platinum Band"), and band 20 is EU Digital Dividend 800 MHz. With those band capabilities, the Nexus 5X will be usable on LTE, W-CDMA, or at least GSM in almost every country on the planet -- though that may require a local SIM card.


Speaking of SIM cards -- which are technically UICC now, but most still call them the colloquial SIM -- the Nexus 5X as expected has a 4FF nano SIM slot. Your 3FF micro SIM from the Nexus 5, for example, will not fit. From a Sprint perspective, since S4GRU is primarily a Sprint focused educational site, this does raise another issue. USIM vs CSIM. For activation and network authentication, USIM is 3GPP only (i.e. LTE/W-CDMA/GSM), while CSIM also incorporates 3GPP2 (i.e. CDMA2000). So, on Sprint, a handset that requires a USIM needs a separate CDMA2000 activation process, but a handset that requires a CSIM activates both LTE and CDMA2000 via the SIM.


At this point, we do not have any info from LG, Google, or Sprint whether the Nexus 5X will require a USIM or CSIM for activation on Sprint. My educated guess is a CSIM -- just like the 2015 Moto X aka Style aka Pure Edition a few weeks ago. But that remains to be seen. Expect some uncertainty for the first few days, but rest assured, it will all get sorted out shortly. And S4GRU will be here to provide information as it emerges. If warranted, we may write another update to this article. You also can follow along in The Forums in our Nexus 5X thread.


Original article:


Two years ago, on a September day forever historic for S4GRU, we discovered and announced to the world the then unrevealed 2013 LG Nexus 5, as its FCC OET (Office of Engineering and Technology) authorization documents made a surprise reappearance, and we noted that the backplate photos included in the filings matched up remarkably well with recent images of a mystery device being used at Google. Indeed, we proved to be right about the LG-D820 and got a nice scoop on the rest of the tech press.


Today, S4GRU comes forth to herald what appears to be the long anticipated successor to the 2013 Nexus 5. The authorization filings for the LG-H790 have been uploaded late today in the FCC OET database. For the write up on the Nexus 6P, click here.



  • Overall (Length x Width): 146.9 mm x 72.5 mm
  • Overall Diagonal 159 mm
  • Display Diagonal: 133 mm

Supported Domestic Airlink Technologies:

  • GSM 850 / 1900
  • W-CDMA Band 2 / 4 / 5
  • CDMA2000 Band Class 0 / 1 / 10
  • LTE Band 2 / 4 / 5 / 7 / 12 / 13 / 17 / 25 / 26 / 29 (Rx only) / 41

A Category 6 UE with support for 2x carrier aggregation on the downlink.


And the supported Carrier Aggregation profiles are as listed (Band #+Band #):


Inter band:
























Intra band:





Carrier aggregation on Verizon? Check.

Carrier Aggregation on ATT? Check.

Carrier Aggregation on T-Mobile? Check.

Carrier Aggregation on Sprint? Yup!


To follow up with some brief RF analysis, let us bring in S4GRU's technical editor...


This expected Nexus 5X is clearly tuned for low and mid band spectrum. That would be primarily Cellular 850 MHz, SMR 800 MHz, PCS 1900 MHz, and AWS-1 1700+2100 MHz. For Sprint purposes, only PCS and SMR are relevant, comprising the CDMA2000 band classes 1 and 10, the LTE bands 25 and 26, respectively. Since LTE is the going concern, know that band 25 maximum EIRP at 26 dBm is excellent, the same for band 26 maximum ERP at 23 dBm.


Unfortunately, high band spectrum does not fare quite as well. The high band antenna covering BRS/EBS 2600 MHz spectrum has a disappointingly low gain of -2.6 dBi. And that seems to be reflected in the band 41 maximum EIRP of 19 dBm, which is low to average, at best.


As this almost obviously is the Nexus 5X -- that we know will be a very interesting device to our readership -- we may do a complete RF testing analysis article down the road. But S4GRU wanted to get the highlights out to everyone right away.


With Google's September 29 reveal event just four days away, this FCC OET authorization comes right on time. The recent Amazon India leak of the Nexus 5X indicated an identification of LG-H791, and now we have an LG-H790. The 2013 Nexus 5 North American variant was LG-D820 and international model was LG-D821, so the number correlation is there.


Should S4GRU be 5X certain that the LG-H790 is the 2015 Nexus 5X? Our track record on these matters is established. But we will let you decide...



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Thanks for the explanation about the difference between CSIM and USIM.


If this phone has a CSIM, does that mean that if I had multiple CSIM phones I could switch between them at will just by swapping the SIMs without having to contact Sprint?

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No, technically, it is a Category 9 modem.  The Snapdragon X10 LTE baseband on die on the Snapdragon 808 chipset is inherently Category 9.  But as implemented with a single RF transceiver upstream, it is limited to Category 6.



Ahh. Oh well. I'll probably still get one.

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Thanks for the explanation about the difference between CSIM and USIM.


If this phone has a CSIM, does that mean that if I had multiple CSIM phones I could switch between them at will just by swapping the SIMs without having to contact Sprint?


In theory, yes.  So long as both devices use exactly the same SIM card size, type and model.

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